The specific aims of this pilot study are: 1) to develop a cell culture system of salivary acinar cells; 2) to study some structural and functional characteristics of the cultured cells. To accomplish these objectives we will first isolate acinar cells from the rat submandibular gland by enzymatic digestion of tissue fragments as routinely done in our laboratory. The cells will then be seeded on three types of support matrices, collagen-polycarbonate supports, nucleopore filters coated with collagen and millipore microporous membranes and incubated at 37degreeC in 5% Co2-air in nutrient media with and without hormonal and metabolic supplements. The media will be changed or replenished at timed intervals and proliferation and confluency will be assessed periodically by light microscopy. A major portion of the initial research will be devoted, therefore, to establishing the optimal conditions for the formation of confluent epithelial cell barriers. Monolayers which develop to confluency with one of the procedures outlined above will then be studied morphologically both at the LM and EM levels. Other monolayers will be placed in Ussing-type chambers for the measurement of transepithelial ion fluxes and electrical potential differences (PD). Net and unidirectional fluxes of 36Cl will be measured in the absence and presence of autonomic agents and transport inhibitors. These findings will be correlated with parallel measurements of PD with KCL-agar bridges connected to a high impedance voltmeter by calomel half cells. The development of a cell culture system of salivary acinar cells will set the basis for a number of future studies related to acinar ion transport under basal and stimulated conditions, which would contribute substantially to our understanding of salivary gland function and regulation.